The article presents the results of research on selected thermal, mechanical properties, as well as the microscopic structure of filaments and details made on a 3D printer in FDM technology. The materials used in the study were PETG (polyethylene terephthalate doped with glycol) and PLA (polylactide) doped with copper. As part of the study, Differential Scanning Calorimetry (DSC) was performed in order to determine the temperatures of phase transformations and changes in melting enthalpy values of filaments before the printing process and also elements made of them. The second part of the research was electrocorrosive ageing process of printouts, carried out in the Simulated Body Fluid solution in a device generating 0.3 A direct current, voltage with value 4.3 V for the entire duration of the test, which was 720 h. After this process DSC test was conducted again. The next stage of the research was Dynamic Mechanical Analysis (DMA) of printouts before and after electrocorrosive ageing process. This test was carried out to characterize the dynamic-mechanical properties as a function of frequency, temperature and time. Additionally, microscopic analyses of the surfaces of the tested printouts were performed in order to assess the changes after electrolysis.
The article has presented the method of 3D Digital Light Processing printing as one of the technologies used for rapid prototyping of dental models and making elements of dentures. in this work the research was presented, which the aim was to determine the effect of additional exposure time on the properties of the obtained printouts. Dynamic Mechanical Analysis test showed significant differences in stiffness between uncured specimens as well as specimens cured for 10, 20 and 30 minutes. in turn the obtained TG and DTG curves allowed to determine the most optimal curing time for DLP printouts. These studies provide the basis for determining the most appropriate method for handling printouts after the process of printing from liquid resin, so that they are the best possible quality for dentists and prosthodontists.
The article has been devoted to issues connected with the alloplasty and hip joint endoprostheses, that elements are being developed, which is supported by strength, tribological tests on used biomaterials, incl. polyethylene or computer modelling based on e.g. finite element method (FEM). In this paper, the results of research on the impact of the material articulations of the system head – acetabular and friction conditions on strength parameters of polyethylene components in the hip joint endoprosthesis. Numerical analysis of this friction node was carried out, using the ADINA System computer program and the simulations were performed at various friction conditions for metal/ polyethylene and ceramic/ polyethylene articulations with various UHMWPE modifications. The simulations results have shown the influence of tested material associations and friction conditions on parameters related to the strength of polyethylene cups, i.e. their displacements, stresses and deformations.
The article presents an assessment of the state of stress and deformation of a personalised tooth protector, taking into account various types of elastomer materials that allow optimal protection of the teeth in contact combat sports. The load characteristics of the personalised protector, perfectly adhering to all, even clearly protruding from the anatomical line of teeth, were calculated using ANSYS 18 software. Numerical simulations of different elastomer materials were compared. Assessment of the state of stress and deformation of the protector allowed to demonstrate the legitimacy of protecting teeth with a personalised tooth protector and to increase the safety of the teeth and soft tissues of the oral cavity in contact combat sports. Based on a dental impression and plaster casting of the jaw made using an eviXscan 3D scanner, its model was digitalised. CAx techniques were used to design a mouthguard. Furthermore, a control code was generated and transmitted to a CNC milling machine to make a mouthguard fitted to the user’s teeth.
PL
W artykule przedstawiono możliwości zaprojektowania spersonalizowanego ochraniacza zębów używanego w kontaktowych sportach walki. Na podstawie pobranego wycisku stomatologicznego i wykonanego gipsowego odlewu szczęki przy pomocy skanera eviXscan 3D został zdigitalizowany jej model. Za pomocą technik CAx zaprojektowano ochraniacz. Następnie na tej podstawie został wygenerowany i przesłany do frezarki CNC kod sterujący. Na frezarce został wykonany ochraniacz dopasowany do zębów. Wykorzystując oprogramowanie ANSYS 18 przedstawiono również przykład obciążeń ochraniacza, ciosami bokserskimi zadawanymi w żuchwę. Omówione zostały znane modele fenomenologiczne opisujące gęstość energii odkształceń materiału hiperelastycznego. Zaproponowana metoda daje możliwość lepszego dopasowania ochraniacza z dowolnie wybranego polimeru, wyższą biokompatybilność ze względu na mniejszą zawartość resztkowego monomeru i eliminuje niedogodności w powszechniej stosowanych elementach z tworzyw termoplastycznych oraz niedopasowanie wynikające ze skurczu materiału.
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Road traffic accidents involving coaches do not happen very often, but they are very dangerous because they affect a large number of passengers. Coaches (or intercity buses) are not equipped with safety belt harnesses. Valid regulations do not impose any obligation on coach manufacturers to provide intercity buses with either two- or three-point safety belts. This fact may result from the unawareness of risks and injuries that might befall the passengers with no safety belts during accidents. That is the reason why this work aims to compare the aftermath of coach accidents with no safety belts and the ones with safety belts. A detailed aim of this research is to analyse the results of dynamic loads during a frontal impact exerted on coach passengers travelling with and without (two- and three-point) safety belts. This objective was achieved by performing experimental studies and modelling which focused on the process of dynamic load transfer on the human body during a traffic accident. The research was conducted parallel on an adult and a child. The equivalent of a 50th percentile male was a hybrid III dummy (M50), whereas a child at the age of about 10 was represented by a P10 dummy. A numerical model was generated and verified in experimental testing in the scope of kinematics. Also, the comparison of the recorded courses of forces, acceleration, and moments was conducted. The results obtained from the tests were analyzed regarding the injury criteria for head, neck, and thorax. It was observed that both for the two-point safety system and the lack of safety belts, there were high values of acceleration recorded in the centre of gravity of the head. On the basis of the investigations conducted, it was ascertained that only a three-point safety belt system ensures the satisfaction of all injury criteria within admissible standards both in the case of criteria defined in the rules no. 80 and the rules no. 94 determined by the United Nations Economic Commission for Europe. It is the three-point safety belt system which should be obligatory in all intercity buses.
Artykuł poświęcono modelowaniu stanu naprężeń i odkształceń kompozytu UHMWPE – włókno węglowe. Część wstępna obejmuje kwestie związane z biomateriałami, kompozytami oraz właściwościami osnowy i włókien analizowanego materiału. Z kolei w części badawczej zaprezentowano zagadnienia dotyczące przygotowania modelu badanego kompozytu oraz wyniki badań z wykorzystaniem metody elementów skończonych obrazujące rozkład naprężeń i odkształceń w materiale powstający w wyniku ściskania.
EN
The article is devoted to modeling the state of stresses and strains for composite UHMWPE – carbon fiber. The introductory part covers issues related to biomaterials, composites and properties of matrix and fibers of analyzed material. In turn, the research part presents issues regarding the preparation of the model of the tested composite and the results of computer simulations, carried out in the ADINA program, illustrating the distribution of stresses and strains of the material resulting from compression.
Artykuł zawiera ocenę jakości wydruku elementów wykonanych w technice druku DLP, poprzez analizę projekcji otrzymanych z tomografu wolumetrycznego i konwencjonalnego. Podczas analizy określono czy możliwym jest wykonanie fantomu do CBCT z wydruku światłoutwardzalnego przy pomocy drukarki DLP. Badania tomograficzne miały na celu określenie obecności wtrąceń materiałowych i pęcherzy powietrza, mogących dawać efekt odbicia promieni rentgenowskich. Przeanalizowano ilość pochłanianej wiązki promieniowania poprzez pomiary wartości jednostek Hounsfielda dla wielu obszarów próbek.
EN
The article has been devoted to an evaluation of the print quality of elements made in the DLP printing technique, which was obtained as a result of the analysis of the projection from the volumetric and conventional CT. During this analysis the presence of air bubbles, material inclusions and other artifacts, which may give the effect of X-ray reflection, was determined. The amount of absorbed radiation beam was also analysed by measuring the Hounsfield unit values for many sample areas.
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